The present invention relates in general to a system and a method adapted to control bow or skew within a web of material to be processed. More particularly, the invention relates to a system and a method used to control any bow and/or skew that may be present within a backing material passed toward the needle bar of a tufting machine.
As known, during the manufacture of carpet or other tufted work products, a primary backing material is supplied from a storage roll and continuously fed in a warp, i.e., a longitudinal or lengthwise, direction through a tufting machine. The tufting machine is provided with a reciprocating needle bar having a series of spaced tufting needles disposed thereon. The tufting needles are each threaded with the yarn to be tufted in the backing material, the needles being passed together through the backing material by the reciprocating motion of the needle bar as the backing material is moved or carried past the needle bar during machine operation to form tufts in the xe2x80x9cfacexe2x80x9d of the backing material.
The backing material may comprise a woven, a non-woven, a knitted, or a needle punched fabric, as well a stitch bonded primary backing material. The backing material therefore comprises a plurality of yarns, fibers, or filaments extending both longitudinally in the warp direction and perpendicularly in a weft direction across the width of the backing material. As one skilled in the art appreciates, materials such as polypropylene, as well as polyesters, hemp, composites, blend, nylons, or cottons, can be used to form the backing material.
A problem that exists in the art, however, is that the backing material made within industry tolerances is often distorted, with the result that oftentimes the weft lines within the backing material will not be aligned with the needle bar of the tufting machine as the backing material is advanced toward the needle bar. Four specific alignment problems result from the backing material being misaligned with the needle bar of the tufting machine. These problems being a xe2x80x9cbow,xe2x80x9d or a xe2x80x9cskewxe2x80x9d in the weft-oriented tufts tufted in the backing material, or the tufted yarns being xe2x80x9chooked,xe2x80x9d and/or extending along a wiggled weft line.
Bow exists within a tufted product when the weft yarns, fibers, or filaments in the backing material are not linear or straight, e.g., there is a curvature in the weft yarns relative to the needle bar. Skew, in comparison, exists when the-weft yarns are not parallel to the needle bar, for example the weft yarns may extend along a straight line, but the line otherwise forms an angle relative to the needle bar. Hook exists when the weft yarns are oriented in a curved, or extend along a non-parallel, line or lines relative to the needle bar along at least a portion of their length, and appears at the edge(s) of the backing material. Wiggle exists when the weft yarns change from any combination of a positive to a negative angle relative to the needle bar in a specific section of the backing material.
Accordingly, when the problems of bow and/or skew occur within the tufts formed in the backing material, the tufted yarns are not parallel to at least a portion of the length of the weft line in the backing material. Thus, when attempting to join two adjacent carpet sections together along their respective weft lines, for example in a large space such as a public concourse or a ballroom, a noticeable difference can be seen in the tufted and/or printed carpet patterns from section to section of the carpet, which results in an undesirable or unsightly appearance in the installed carpet.
Examples of known devices and systems which attempt to address the problems of bow and skew in tufted products are found in U.S. Pat. No. 4,255,050 to Beckstein et al., U.S. Pat. No. 4,261,498 to Short, U.S. Pat. No. 4,364,502 to Fentress, and U.S. Pat. No. 5,035,030 to Pellari. Additional patents which may be relevant to this problem are U.S. Pat. No. 4,656,360 to Maddox et al., U.S. Pat. No. 4,987,663 to Epple, and U.S. Pat. No. 5,416,593 to Vercruysse.
What is needed, therefore, but seemingly unavailable among the known devices, is an improved system and a method for controlling, i.e., for reducing or eliminating to the greatest extent possible, the bow and skew of a backing material fed through a tufting machine.
The present invention overcomes some of the design deficiencies of the known art by providing an improved system and a method for controlling the presence of any bow and/or skew within a backing material to be fed through a tufting machine. This is accomplished by providing such a system and method in association for use with a conventional tufting machine having a reciprocating needle bar disposed with respect to a tufting zone through which the backing material is fed, a cloth feed roll positioned upstream of the tufting zone for moving the backing material toward the tufting zone, and a roll of backing material from which the backing material is supplied. The backing material may be of woven or of non-woven construction, and will be comprised of a plurality of elongate warp yarns, fibers, or filaments extending longitudinally in the lengthwise direction of the backing material, and a plurality of weft yarns, fibers, or filaments extending substantially perpendicular to the warp yarns and in the cross-length direction of the backing material. The terms yarn, fiber, and filament are used interchangeably herein, and refer to the aforementioned warp and weft yarns, fibers, or filaments within a woven or a non-woven backing material, respectively.
In a first embodiment, the method of the invention includes aligning at least one elongate weft yarn marker disposed on the backing material with the needle bar so that the at least one weft yarn marker is parallel to the needle bar. The at least one weft yarn marker is disposed on or within the backing such that it is parallel to the weft yarns of the backing material. This method may also include the aspect of detecting whether the at least one weft yarn marker is parallel to the needle bar as the backing material is passed toward the tufting zone.
The method may also include detecting a plurality of closely spaced and substantially parallel weft yarn markers formed as a group of weft yarn markers on the backing material, and of detecting a series of weft yarn marker groups spaced in the lengthwise direction of the backing material. In an alternate embodiment, the method comprises detecting the at least one weft yarn marker as the backing material is being passed toward the tufting zone, and aligning the at least one weft yarn marker with the needle bar so that the at least one weft yarn marker is parallel to the needle bar. This may be done with an automated detection device, or by manually observing the at least one weft yarn marker with respect to the needle bar of the tufting machine.
Yet another embodiment of the method therefore comprises physically observing, i.e., manually or visually detecting, the at least one weft yarn marker with respect to the needle bar as the backing material is passed toward the tufting zone, and aligning, either automatically or manually, the at least one weft yarn marker with the needle bar so that the at least one weft yarn marker is substantially parallel to the needle bar.
The method further comprises positioning a bow roll intermediate the roll of backing material and the cloth feed roll and used to selectively increase and decrease the tension of at least a portion of the backing material; and alternately, to increase and decrease the tension of a central portion of the backing material in response to the detection of the at least one weft yarn not being substantially parallel to the needle bar in order to control any bow that may be present in the weft yarns of the backing material with respect thereto.
The method also comprises mounting the roll of backing material on at least one jack assembly, or on a pair of spaced jack assemblies positioned at the ends of the roll of backing material, each such jack assembly being constructed and arranged to independently and selectively raise and lower the respective ends of the roll of backing material for increasing and decreasing the tension of at least a portion of the backing material, preferably the two spaced and separate portions thereof extending along the respective separate side edge portions of the roll of backing material, in response to the detection of the at least one weft yarn not being parallel to the needle bar, and for controlling any skew that may be present in the weft yarns of the backing material.
The system of the invention, adapted for use with a tufting machine as described above, includes in a first embodiment at least one weft yarn marker disposed on the backing material, the at least one weft yarn marker being parallel to the weft yarns of the backing material; at least one detection device positioned with respect to the needle bar and being constructed and arranged to detect the at least one weft yarn marker as the backing material is being passed toward the tufting zone; a bow roll positioned intermediate the roll of backing material and the cloth feed roll; and a controller operably coupled to the at least one detection device and the bow roll. This embodiment of the system may also comprise at least one jack assembly, or a pair of jack assemblies, as described and operated above, each such jack assembly being operably coupled to and controlled by the system controller. Each of the bow roll and the at least one jack assembly includes an actuator constructed and arranged to move the bow roll against the backing material, or to lift an end, or the ends, of the backing material supply, respectively, as desired.
The at least one detection device is preferably positioned downstream of the cloth feed roller, and parallel to the needle bar of the tufting machine. The at least one detection device may comprise a plurality of detectors, for example three such detectors, spaced from and aligned with one another in the weft direction of the backing material, and each of which is positioned parallel to the needle bar. The detector(s) will preferably be selected from among the group of detectors comprising optical, laser, magnetic, electronic, infra-red, and ultrasonic detectors, with the at least one weft yarn marker being selected from among of the markers within the group of markers comprising optical, laser readable, magnetic, electronic, infra-red, and ultrasonic markers.
The at least one weft yarn marker of the system preferably comprises a series of parallel weft yarn markers spaced from one another in the lengthwise or warp direction of the backing material, and each of which is parallel to the weft yarns of the backing material. In another embodiment, the at least one weft yarn marker comprises a plurality of closely spaced and parallel weft yarn markers disposed on the backing material and formed as a group of weft yarn markers, each of the weft yarn markers within the group being spaced from one another in the lengthwise direction of the backing material and being parallel to the weft yarns thereof. In a further aspect, therefore, there is a series of spaced groups of weft yarn markers extending in the lengthwise direction of the backing material. The weft yarn markers within each group of weft yarn markers are disposed parallel to the weft yarns of the backing material.
In each of the system embodiments, the controller is constructed and arranged to selectively instruct a first actuator operably coupled to the bow roll to move the bow roll against the backing material, and will also selectively instruct at least one second actuator operably coupled to each jack assembly to raise and lower at least one end of the roll of backing material, respectively, for increasing and/or deceasing the tension of the backing material passed toward the tufting zone in response to the detection of the at least one weft yarn marker not being substantially parallel to the needle bar. The controller may be automated, or manually operated, as desired.
The present invention is therefore particularly advantageous when positioning or laying sections of tufted carpet immediately adjacent each other as the carpet pattern alignment across the carpet seams should not be discernible due to the improved alignment of the weft yarns or filaments, such that the carpet will not exhibit bowing, skewing, hooking, or other distortions of the pattern that would create a visible pattern misalignment.
It is also contemplated using the present invention to properly align and tuft multiple primary backings simultaneously with a single tufting machine. In one embodiment, one tufting machine will tuft two primary backings in a side-by-side arrangement. Two separate systems of the present invention, one for each primary backing, may therefore be provided and each of which operates independently of the another. Alternately, therefore, the present invention allows for the alignment of a primary backing, a lower primary backing, or both of an upper and a lower primary backing, independently of each other.